From the very earliest days of computing, programmers have been forced to target applications to particular screen sizes and resolutions. Even the flexibility of the Web's HTML imposes these kinds of limits, with some pages looking good on some resolutions while having a poor appearance on others.
This situation was awkward yet manageable, while most of the world's information displays were confined to fixed computer monitors and televisions, most with industry-standard sizes and resolutions. But now, with the introduction of lightweight, low power consumption displays with wide size variation, such as liquid crystal displays and plasma units, the former display constraints are being removed. Nowadays programmers and content creators cannot make assumptions about the devices that will display the delivered information. To do so introduces inherent weaknesses in the way their content can be accessed and linked with other information.
Generally speaking, the IT industry has reacted to this challenge using traditional notions of ‘device independence’. The seminal model of this approach to content presentation is Adobe's Page Description Format (PDF). This digital file type uses similar formatting commands across a multitude of devices, thus ensuring the correct display of documents on whatever system is used to render the output to the user. This ensures the information looks the same whatever resolution it displays on, with detail being degraded on less sophisticated rendering devices. However this detail is not lost if viewed on a low resolution monitor, as the user can often zoom in if desired.
Although this method preserves the original fidelity of the information's look and feel, PDF files are static, typically being rendered to a pre-determined paper size. The end-user's device is expected to navigate around this. This can be difficult, particularly if the original document was rendered to a size much larger than the end-user's device, such as trying to look at a Foolscap page on a cell phone sized display. Intrinsic to this method of information distribution is the expense of converting documents from their original form to the description language of PDF. Such conversions can limit a document's reuse, with recipients experiencing difficulty re-editing and thus reusing the information in a similar form in different contexts.
The problem is exacerbated in Web pages where formatting is mixed up with the substance of content. It is not always easy to determine whether content is a bitmap picture, a textural heading bitmap, a navigational token bitmap or all or only some of the above. It is also difficult to determine whether a table is a logical unit of information or a layout separator. The ambiguity of display formats often compromises the ability of display devices to render the information in a way that suits the end-user environment. So file formats such as PDF and HTML often result in compromised viewing situations when rendered by devices not originally targeted by a document creator. This is becoming increasingly unmanageable in today's world of device proliferation, where advances in battery, communications and flat display technology are multiplying end user display options.
To overcome these deficiencies, many in the IT industry propose a different kind of device-independent format. Using standards such as XML, information presentations as diverse as text, pictures and program user interfaces are being described in a manner whereby the substance of the content is stored separately from its layout or display formatting instructions. This provides the display device with the opportunity to make value judgments on how content should be displayed, both in the context of its use and the display environment in which it is to be rendered.
While this may be a great step forward in solving technical issues it results in content creators, publishers and developers losing control of how information is to be displayed. This is unacceptable because the look and feel of documents and programs is an essential ingredient for product differentiation. Moreover, content is often deliberately presented by its creator in such a way as to give more or less significance to its various parts. So altering the look and feel of content for convenient display might also change its intended meaning.
Of even greater concern is the arbitrary degradation of information that each end-user device may impose when rendering information on low resolution systems. The look and feel of the document, including the layout and navigation, is sometimes completely different from what is rendered on higher resolution displays. This forces users to learn a different way of using an application or document on each class of device displaying the information.
So while abstracting content away from its format is technically possible, in practice formatting and layout provides a context which gives meaning to content. This has been addressed in part by employing templates, which when applied alter XML documents to be more suited to their intended display environments. This offers some improvement compared to static formats such as PDF or HTML. Individual document conversion and hard coding can be abolished, being handled once for each device and each document class or application type using a complex matrix of templates.
However using device and document templates with XML cannot eliminate all of the rendering disadvantages due to multiple display sizes. The use of templates assumes developers and content creators can know in advance all the device types that will try to render their information. And having no control over these devices makes content degradation and user interface variation inevitable. This is caused by differences in capabilities between devices, as mandated by their size, capacity of their power source and indented use, creating learning curves to effectively present the same content across multiple device types. Altering XML documents with templates this way may also compromise their reusability when passed to other rendering engines or editors on more advanced systems.
Another problem that is not addressed by either flexible XML or fixed description formats is the formatting issues associated with document readability over different viewing distances. For example, a billboard sized screen may have four million pixels. A hand-held device may have the same. One user's eyes are 30 centimeters away; another's are 30 meters away. But even when two users look at the same device from the same distance, different magnifications of the content may be appropriate, depending on the quality of their eyesight. This is a key usability flaw in all device-centric formatting regimes, be they fixed or flexible.
The problems above are further compounded by modern end-users being connected through networks such as the Internet. In times past, most users accessed information from one or at the most two devices—their desktop or notebook PC. But in a world of inter-connected devices, users may soon expect to be able to read documents located on their PC or business servers on any handheld device via a wireless link, for example a mobile phone. Therefore these problems are being encountered by users sharing documents, as well as where a reader and author are the same person.
The range of possible display sizes information must be accessible through is further being proliferated through portal technology. Portals assemble information on behalf of end-users, typically presenting it on Web pages made up of a series of ‘info-boxes’. Even info boxes displaying the same information may vary in size, depending on how important each end-user considers the contained information to be. Therefore the arbitrary nature of portal information viewing areas means maintaining a consistent look and feel to content is becoming even harder to achieve.
What is lacking is a presentation system which strikes a balance between the competing interests of end-user preferences, document owner/creator desires, rendering device constraints and network transmission considerations. This must be achieved in such a way as to preserve the content's look and feel, navigability, usability and reuse, with high fidelity across a multitude of devices.
Prior patent documents have been identified that relate to the reformatting of documents. Reference may be had to U.S. Patent Application No. 2001-0011364, in the name of Stroub. Stroub reformats documents into columns that have a fixed number of characters per line. The number of columns is selected to suit a given screen. The approach of Stroub is useful for simple text but is of limited value for more complex content.
Another approach is described in U.S. Pat. No. 6,175,845 in the name of IBM Corp. The IBM approach is to implement navigation between parts of a document by inferring the significance of content to users. Not having a unique multi-user, multi resolution, multi-magnification cache, the system reformats content each time it is requested by the user or when the user resizes the viewing area. However content-based analysis and per-view reformatting on demand are particularly processor intensive mechanisms for the display of content. As a result, this method is impractical for most applications.
In U.S. Pat. No. 5,818,446 IBM Corp also describes a system for changing user interfaces, principally document navigation, again based on analyzing the information being displayed. Using display software to change the user interface according to certain criteria which is compared against the characteristics of the content on hand has some glaring limitations. The method doesn't deal with critical factors influencing usability such as display area size and requires end-users to learn multiple interfaces to view content on the same device.
The prior art does not describe a system or method which reformats documents for display on varying display types while minimizing repeat processing and optimizing display for optional transmission over a computer network.